It is frequently required that an air separation unit producing a gaseous component of air under pressure should also produce a varying amount of a component of air in liquid form.
It is known to supply this requirement by having an air separation unit to produce the gaseous component under pressure, the air separation unit being associated with a liquefier to liquefy varying amounts of gas from the air separation unit to produce the liquid. This apparatus involves considerable capital expenditure.
According to the invention, there is provided a new process scheme which operates efficiently in the gas mode and the liquid mode whilst involving only reasonable investment costs.
All percentages mentioned are molar percentages.